To erect a vertical concrete wall, pre-cast tilt-up concrete panels are commonly used. Another commonly used technique is to use formwork in-situ to support the concrete and reinforcing bars until the concrete has set and cured, after which the formwork is removed.
An alternative way of constructing walls is to manufacture hollow panels which can be manufactured off site, delivered to the building site, erected and filled with concrete on site. These hollow panels consist of two formwork wall board sheets separated by spacers which hold both the vertical and horizontal bars in correct alignment and facilitate the flow of concrete. These panels are then sacrificed as they remain in place and their surface acts as the interior and exterior surfaces of the wall. When erecting these hollow panels, vertical aluminium or galvanised steel studs can be used to support the formwork wall board sheets and position and hold the horizontal and vertical steel reinforcing bars within the formwork prior to the concrete being poured. Aluminium and steel stud frames have the disadvantage of being heavy making the panels difficult to handle. Panels are also prone to distortion due to the flexibility of the studs. In addition, the steel frames can be prone to rusting as the outer edge of the steel studs are not covered by concrete, only by the formwork wall board sheet. Further, the aluminium frames can corrode when in contact with concrete.
Another way of constructing walls is to position box or cube shaped spacers between opposing formwork boards in a spaced relationship. Vertical and horizontal reinforcing rods are then placed through each of the wall spacers to keep the wall construction aligned while the concrete is poured. Operators using this system often misalign or incorrectly place the box shaped spacers making it difficult to place the reinforcing bars in the formwork. Further, due to this wall construction system requiring a disposable template for the accurate positioning of box spacers, the system is difficult to automate.
Discussion or mention of any piece of prior art in this specification is not to be taken as an admission that the prior art is part of the common general knowledge of the skilled addressee of the specification in Australia or any other country.
It would be advantageous to provide an improved, inexpensive, easily constructed and lightweight means of constructing a concrete wall.